Apparatus for dragging along a submerged structure

ABSTRACT

Apparatus for dragging along a structure submerged in a body of water is attached by a pulling cable to the structure and is carried by the lower end of a pole or post which depends from a floating vessel and is mounted by a universal joint on said vessel. A cable extends from a winch on the vessel down over a pulley carried by the lower end of the pole to an anchor towards which the vessel and submerged structure are to be drawn and means are provided for moving the pole upwardly or downwardly to adjust the position of the lower end of the pole relative to the floor of the body of water.

United States Patent 1 1 Hinkle l l Oct. 2, 1973 APPARATUS FOR DRAGGINGALONG A SUBMERGED STRUCTURE George S. Hinkle, Wassenaar, Netherlandslnvcntor:

Assignee: R. J. Brown and Associates Filed: May 26, 1971 Appl. No.:146,960

Foreign Application Priority Data May 27. 1970 Netherlands 7007662 US.Cl. 115/7, 6l/72.3 int. Cl B63b 21/56 Field oiSearch 115/7; 61/723, 72.4

7 References Cited 0 UNITED STATES PATENTS Stimson (H/72.3

3590,58) 7/l97l Smulders t. (ii/72.4

Primary Examiner-Milton Buchler Assistant Examiner-Stuart .M. GoldsteinAtt0rneyYoung & Thompson [57] ABSTRACT Apparatus for dragging along astructure submerged in a body of water is attached by a pulling cable tothe structure and is carried by the lower end of a pole or post whichdepends from a floating vessel and is mounted by a universal joint onsaid vessel. A cable extends from a winch on the vessel down over apulley carried by the lower end of the pole to an anchor towards whichthe vessel and submerged structure are to be drawn and means areprovided for moving the pole upwardly or downwardly to adjust theposition of the lower end of the pole relative to the floor ofthe bodyof water.

7 Claims, 1 Drawing Figure Pmmanw m 3.782.358

INVENTOR 650665 6. H/NKME BY M ATTORNEY$ 1 APPARATUS FOR DRAGGING ALONGA SUBMERGED STRUCTURE The invention relates to an apparatus for draggingalong a structure which is either directly or indirectly resting on thefloor of a body of water by means of a cable connected with saidstructure.

It is known in the art, for instance, to drag pipe-laying devices alongthe pipeline. In that instance, the device is dragged along by means ofa cable extending from a vessel which may or may not be at anchor. Thepower required for energizing said pipe-laying device is in thatinstance supplied by tubes or cables extending from the vessel as well.The disadvantage of this known apparatus is that the cable does notalways pull in the desired vertical or horizontal direction, while themovements of the vessel due to the wash of the waves is an interferingfactor. Moreover, the orientation of the vessel with respect to waves,currents and wind may be unfavorable.

It is therefore an object of the present invention to provide anapparatus for dragging along a submerged structure in which saiddisadvantages are eliminated. This object is achieved by the fact thatthe pulling cable is secured to a member which is permitted to swing andadapted to be kept above the floor of a body of water in front of thestructure from a vessel or a similar floating installation and by thefact that a second cable extends from said member, which is retained atsome distance from and in front of said member and roughly in thedirection of movement, means being provided to haul in said second cablewith respect to said member.

In this manner it is achieved that under all conditions the structure issubjected to a pulling force in the desired direction, whereby thevertical component of said force may be adjusted as desired, while theorientation of the vessel can be chosen independently from the directionin which the force is exerted.

The member may be secured to the lower portion of a pole suspended fromthe vessel, which pole is universally pivotable and is connected withthe vessel in a vertically adjustable manner, the second cable beingpassed via a sheave mounted on the member to a winch drum for hauling insaid cable, which drum is mounted on the vessel.

In order to make it possible to adjust the pulling force to the desiredextent, means for controlling said force may be provided at the secondcable.

In order to maintain the position of the member at a constant levelabove the floor of a body of water, the pole may be suspended via meansfor the compensation of vertical difi'erences in height. Means may bepro vided for lowering the pole.

In applying the apparatus for dragging along a structure according tothe invention, which has to be eiiergized, the tubes or cables for thesupply of the power are passed through the pole. Due to the fact that inthe apparatus according to the invention there is a constant distancebetween the structure to be dragged along and the lower portion of thepole, there is no danger that said tubes may become entangled.

The invention will now be explained in more detail with reference to thesingle FIGURE of the drawing, wherein a diagrammatic fragmentary view ofan embodiment of the invention is shown.

The drawing shows a vessel 1 floating on the surface of the water. Fromthe vessel 1 is suspended a pole 2 which is passed through the universaljoint 3 mounted on the vessel 1 and down through the opening la. Theuniversal joint 3 is positioned in the proximity of the central axis ofrotation of the vessel 1 so that the lower end of the pole 2 and themember 11 carried thereby will be positioned in the proximity of thecentral axis of rotation of said vessel. To the top of the pole areconnected a hoisting rope 4 and a rope 4a for pulling the pole 2 down,which enable the pole to be moved upwardly and downwardly by means, notfurther shown, disposed on the vessel. At the lower portion of the poleis secured a member 11 to which is attached a cable 5 which, at itsother end, is attached to the structure to be dragged along, which isnot shown and may consist of a pipeline burying device passed over thepipeline 6. At the other side of the member 11 carried by the lowerportion of the pole 2 is mounted a sheave 7, over which sheave a secondcable 8 is passed, the front end of which, not shown, is anchored in thefloor of a body of water, said cable extending upwardly via the sheave 7to the power control means 9 and finally to the winch drum 10 mounted onthe vessel.

When the pulling forces on cable 8 are great and/or the weight of pole 2is light there is a tendency for pole 2 to move upwardly. Rope 4a servesto prevent pole 2 from moving upwardly.

For reasons of safety, member 11 is attached to pole 2 by a fracturejoint so that if the structure to be dragged along should become stuck,for instance, member 11 can break off, said member being secured to abuoy 12 to make it possible to find the broken-off portion again.

The vessel is moreover provided with an echo sounder 13 which makes itpossible to adjust the distance between the lower portion of the poleand the bottom, which echo sounder may cooperate with an adjustingdevice for theadjustment of vertical differences in height, so that thelower portionof the pole remains at a uniform level above the floor of abody of water.

The structure to be dragged along is energized through the cables ortubes 14 which extend from said structure to the lower portion of thepole 2 and are subsequently passed through the pole 2 to the vessel.

In accordance with the present invention there is pro? vided anapparatus by means of which an underwater structure can be dragged alongfrom a vessel in a simple manner. The movements of the vessel do notinterfere with the process, while the longitudinal orientation of thevessel can be substantially independent of the'direction of pull, sothat it is, for instance, nearly always possible to carry out operationswhile meeting the waves bow on.

Having described my invention, I claim:

1. Apparatus for dragging along a structure submerged in a body of waterby means of a pulling cable connected with said structure, comprising amember to which the pulling cable is connected, said member beingcarried beneath a vessel or a similar body floating on said body ofwater and which is permitted to swing and adapted to be kept in front ofsaid structure, said pulling cable extending rearwardly from said memberto said structure, a second cable one end of which is retained at somedistance from and in front of said member and roughly in the directionof movement, and means on said vessel for hauling in the other end ofsaid second cable to draw the vessel and structure towards the retainedend of the second cable, said member being secured to the lower end of apole suspended from said vessel, which pole is universally pivotally andvertically adjustably connected with said vessel, and said other end ofsaid second cable being passed over a sheave mounted on said member to awinch drum mounted on said vessel, in order to haul in said cable.

2. Apparatus for dragging along a structure submerged in a body of waterby means of a pulling cable connected with said structure, comprising amember to which the pulling cable is connected, said member beingcarried beneath a vessel or a similar body floating on said body ofwater and which is permitted to swing and adapted to be kept in front ofsaid structure, said pulling cable extending rearwardly from said memberto said structure, a second cable one end of which is retained at somedistance from and in front of said member and roughly in the directionof movement, and means on said vessel for hauling in the other end ofsaid second cable to draw the vessel and structure towards the retainedend of the second cable, said member being positioned relative to thevessel in the proximity of the central axis of rotation of said vessel,said member being secured to the lower end of a pole suspended from saidvessel, which pole is universally pivotally and vertically adjustablyconnected with said vessel, and said other end of said second cablebeing passed over a sheave mounted on said member to a winch drummounted on said vessel, in order to haul in said cable.

3. Apparatus according to claim 1, in which there is provided a controldevice for controlling the pulling force of the second cable.

4. Apparatus according to claim 2, in which there is provided a controldevice for controlling the pulling force of the second cable.

5. Apparatus according to claim 1, in which there is provided a devicefor the compensation of vertical differences in height of the pole, sothat, the elevation of said member above the floor of the body of waterremains constant.

6. Apparatus according to claim 1, in which there are provided means forpulling down the pole.

7. Apparatus according to claim 5, in which the structure has to beenergized, and means for the supply of power to the structure from thevessel are passed through the pole.

* i III

1. Apparatus for dragging along a structure submerged in a body of waterby means of a pulling cable connected with said structure, comprising amember to which the pulling cable is connected, said member beingcarried beneath a vessel or a similar body floating on said body ofwater and which is permitted to swing and adapted to be kept in front ofsaid structure, said pulling cable extending rearwardly from said memberto said structure, a second cable one end of which is retained at somedistance from and in front of said member and roughly in the directionof movement, and means on said vessel for hauling in the other end ofsaid second cable to draw the vessel and structure towards the retainedend of the second cable, said member being secured to the lower end of apole suspended from said vessel, which pole is universally pivotally andvertically adjustably connected with said vessel, and saiD other end ofsaid second cable being passed over a sheave mounted on said member to awinch drum mounted on said vessel, in order to haul in said cable. 2.Apparatus for dragging along a structure submerged in a body of water bymeans of a pulling cable connected with said structure, comprising amember to which the pulling cable is connected, said member beingcarried beneath a vessel or a similar body floating on said body ofwater and which is permitted to swing and adapted to be kept in front ofsaid structure, said pulling cable extending rearwardly from said memberto said structure, a second cable one end of which is retained at somedistance from and in front of said member and roughly in the directionof movement, and means on said vessel for hauling in the other end ofsaid second cable to draw the vessel and structure towards the retainedend of the second cable, said member being positioned relative to thevessel in the proximity of the central axis of rotation of said vessel,said member being secured to the lower end of a pole suspended from saidvessel, which pole is universally pivotally and vertically adjustablyconnected with said vessel, and said other end of said second cablebeing passed over a sheave mounted on said member to a winch drummounted on said vessel, in order to haul in said cable.
 3. Apparatusaccording to claim 1, in which there is provided a control device forcontrolling the pulling force of the second cable.
 4. Apparatusaccording to claim 2, in which there is provided a control device forcontrolling the pulling force of the second cable.
 5. Apparatusaccording to claim 1, in which there is provided a device for thecompensation of vertical differences in height of the pole, so that, theelevation of said member above the floor of the body of water remainsconstant.
 6. Apparatus according to claim 1, in which there are providedmeans for pulling down the pole.
 7. Apparatus according to claim 5, inwhich the structure has to be energized, and means for the supply ofpower to the structure from the vessel are passed through the pole.